Basic anatomy of the human body

Describe the basic anatomy of the human body affected by assisting and moving The human body is only able to assume it’s different posture and maintain its structure due to the skeletal system. The skeletal system is made up of bones which have an outer hard cortical layer and an inner soft trabecular layer made of cancellous bone. Within some long bone is the all important marrow from where all the blood cells originate after maturation. The skeletal system can be divided into 2 groups:

1.Axial skeleton: The bones here include the skull and bones of the vertebrae column. The skull is subdivided into the 8 cranial bones and 14 facial bones, while the vertebrae column is made up of the following; 7 cervical bones, 7 thoracic bone, 5 lumbar bones, 5 sacral bones and 4 coccygeal bones (all fused into 1 in the adult life). 2.Appendicular skeleton: The bones here include those of the limbs and limb girdles. The limbs are made up of long and short bones in the upper and lower limbs, while the girdles are made up of the pectoral and pelvic girdles Function of the skeletal system includes:

•Shape and support of the human body is all due to our skeletal system. The curvature of the vertebrae column bones plays a major role in our upright posture. So people with bone conditions like osteogenesis imperfecta (genetic malformation) where the skeletal system are poorly formed, the patients are not just prone to fractures but have poorly moulded bones and irregular postures.

•The skeletal system is also the site of insertion of muscles and ligaments. Muscles are attached to bones via tendons for example, the distal biceps tendon attaches the bicep muscle to both forearm bones (radius and ulna); while ligaments holds different bones together at a joint, for example ligaments hold the femur and the tibia bones together at the knee joint. Other functions includes:

•They help protect vital structures in the human body. For instance, the bones of the skull protects the soft brain, while the spinal cord is protected by the vertebrae column bones. The bones that make up the thoracic cage protect the heart, lungs and great blood vessels, while the pelvic girdle protects the genital and gonadal organs particularly in the female e.g the ovaries and uterus.

•Some bones, particularly the long bones have friable structures called the bone marrow. These are sites of blood cell production and maturation. Types and location of bones

Types of bone
Examples of bone
Location
Long bones
Femur, Tibia, Fibula; Humerus, Radius, Ulna
Lower and upper limbs respectively
Short bones
Carpal and Tarsals
Wrist and ankle respectively
Irregular bones
Vertebrae column
Backbone
Sesamoid bones
Patella and metatarsal
Knee and foot
Flat bones
Ribs, sternum and temporal, parietal, occipital bones
Thorax and cranium

Joints: The meeting point of 2 or more bones is called a joint. Joints are not just made up of bones but also will find; cartilage, ligaments, muscles and a times synovial fluid surrounded by a synovial sac. Joints allow movement of 2 or more bones that make it up. Types of joint: They include

•Fibrous joint: These are made up of tough collagen fibres binding bones that make up the joint, for example, sutures in the bones of the cranium and the syndesmosis joint of the ulna and radius bones of the forearm
•Cartilaginous joint: These are joints with cartilage binding or connecting the bones that make up the joint, for instance, the coastal cartilage binding the ribs and the sternum in the thoracic cage and the intervertebral disc of the vertebral column.
•Synovial joint: These joints have a special feature which is a sac called the synovial sac that houses an oily fluid called the synovial fluid. This reinforces the joint and help prevent waring off at the ends of the bones that make up the joint. The following are types of synovial joints:

Types of synovial joint
Location
Range of movement
Gliding
Carpal bones of the wrist
Gliding over each other
Hinge
Knee and elbow joint
Movement in only one direction
Saddle joint
The 1st metatarsal and trapezium ie the thumb
360 degrees movement
Ball and socket
Hip and shoulder joint
Allows for full range of movement hence the one most prone to dislocation.

Muscles: These are bundles of tissues which when contracting can bring about movement in the human body and supporting structures too. Types of muscles:
•Skeletal muscle: They are referred to as voluntary muscles as their contract and relaxation are under the control of will ie, they can be controlled as you wish. They are attached to bones and bring about the movement of this bones across joints. Some skeletal muscles are dynamic; this means they are in constant use ie they are constantly contracting and relaxing. Examples are the muscles surrounding the knee, elbow, hip and shoulder joints. They are well vascularised, as this encourages an ample supply of nutrients and oxygen. Others are static for example the latissimus dorsi muscles on the back are usually in a contracted state (for support and posture) hence it’s blood supply isn’t rich. If this muscles are then used in such a way that results in their constant motion, it could cause aches and pain due to getting damaged.

•Myocardial muscles: They are muscles around the heart. They are involuntary, ie, not under will power, cannot be controlled. They are responsible for the pumping action of the heart. •Smooth muscles: Like the cardiac muscles, they are involuntary and are found in the lining of various organs in the body for example, the intestine where they bring about peristalsis, the blood vessels where they cause vasoconstriction and vasodilation, iris of the eyes where they dilate or constrict the pupil due to the amount of light they are exposed to and many more. The vertebrae column: These uniquely shaped bones are located centrally on the back running from the base of the skull to the beginning of the perineum. It is made up of the following bones •Cervical vertebrae. There are 7 of them in number. They are found in the neck. The 1st of the Cervical vertebrae is called the Atlas. Found right at the base of the neck. It’s articulation with the skull brings about the nodding movement (‘yes’).

The 2nd Cervical bone is called the Axis. This bone has a special feature known as the odontoid process which articulates with the Atlas bringing about the rotatory movement (‘no’). •Thoracic vertebrae. There are 12 in total. Located in the posterior wall of the thoracic cavity •Lumbar vertebrae. 5 in all. They are individually the largest bones in the vertebrae column. This is so because of the weight of the abdominal cavity they bear. •Sacral vertebrae. Unique in the sense that the 5 Sacral bones are individual bones in childhood but fused together in adulthood. They make up the posterior wall of the pelvic cavity. •The Coccygeal vertebrae. There are 4 of them. Again, they are fused bones too. Supporting this bones are the intervertebral disc which are located between individuals vertebrae and act as shock absorbers (cushion). Besides the disc, the vertebrae bones are also supported by ligaments which run the whole length of the vertebrae column.

The vertebrae column have the friable spinal cord running almost it’s whole length (terminates at the lumbar region), where it is protected. Emerging from the spinal cord are nerve roots which innervates muscles and organs in the human body. The vertebrae column have a special curvature particularly in the lumbar region where it is concave. A change in curvature due to excessive movement will push the intervertebral disc posteriorly resulting in it’s compression of the spinal cord. Generally, the vertebrae column bones are allowed only limited mobility. An exaggerated movement due to poor posturing or moving and handling techniques or manual lifting of heavy objects can cause a great deal of damage to the nerve roots or spinal cord causing pain, aches and morbidity. The bony structure, joints and muscles making up the musculoskeletal system are at risk of injuries if manual handling or moving of individuals or objects isn’t done with great care and properly.